POSTERIOR-FOSSA NEUROVASCULAR ANOMALIES IN ESSENTIAL-HYPERTENSION

Intraoperative observations, necropsy, and angiographic studies suppor t the presumption that neurovascular compression of the left ventrolat eral medulla may cause neurogenic hypertension. Pulsatile irritation o f the ventrolateral medulla at the root-entry zone of cranial nerves I X and X increases blood pressure in animals. To identify and assess th e distribution of neurovascular compression at the ventrolateral medul la in human beings, we did a prospective single-blind study in 24 pati ents with essential hypertension, in 14 patients with renal hypertensi on, and in 14 normal subjects. To detect neurovascular compression, we used axial and coronal and magnetic-resonance angiography Blood press ure control and duration of hypertension were not different in the two groups of patients. 20 patients with essential hypertension had magne tic tomographic evidence of left-sided neurovascular compression at th e ventrolateral medulla; 2 patients with renal hypertension and 1 of t he normal subjects had a positive finding on the left. On the right si de, we found signs of neurovascular compression in 4 patients with ess ential hypertension, in 4 with renal hypertension, and in 2 of the nor mal subjects. With magnetic resonance tomography, it is possible to ev aluate the neurovascular relations in the posterior fossa and detect n eurovascular compression at the ventrolateral medulla. These data in l iving subjects give further evidence of an association between neurova scular compression at the left ventrolateral medulla acid essential hy pertension.